Isolation And Identification Of Soybean Fusarium Wilt Pathogenic Fungi In Langfang

Soybean wilt disease caused by Fusarium is one of soil born fungal diseases,which widely distributes,causes serious damage and difficult to control.It also occurs heavily in primary soybean production regions of China,causing serious yield losses,especially when co-occur with soybean cyst nematode Heterodera glycine.Identification of fungi pathogeny of soybean Fusarium is beneficial for prevention,control,reducing the harm to soybean plants,and increase the yield of soybean.Soybean with wilt disease was got in field happened with soybean cyst nematode disease in Langfang of Hebei province.338 strains Fusarium were isolated in vascular from soybean root or stem and cultured on PDA medium to observe the characteristics of the pathogenic fungus.Eight strains of pathogenic fungi were identified by specific primers which 186 strains of Fusarium oxysporum(55.0%),67 strains of Fusarium solani(19.8%),16 strains of Fusarium graminearum(4.7%),1strains of Fusarium avenaceum(0.3%),1 strains of layers of Fusarium proliferaum equisetum hiemale Fusarium equiseti(0.3%),2 strains of dahliae Verticillium(0.6%).The results showed that Fusarium oxysporum might be the dominant pathogen of soybean Fusarium wilt.Fusarium oxysporum conidia classified large and small conidial.Fusarium oxysporum small spores of soybean PI 437654,Qi Huang 34,Holland 12 beans,Wandou 28,11 Pan beans,beans stone No.5,October blue,Gandou 5,43 in yellow,Cang beans 10 No,Jidou 12,and yellow 42,WM82 and the yellow 51 and many more 14 varieties were inoculated bevelledly.The experimental results showed,in addition to WM82,other 13 soybean varieties had different levels of damage symptoms.17 days after infection,the vascular browning occured in Qi Huang 34stem;the vascular browning occured in He Dou 12 injection inoculated stem,These results indicated that small spores were not suitable for disease back test experiments.Large conidia of Fusarium oxysporum was inculated the sensitive varietyHefeng 47 for 24 hours,the apparent wilting was observed.after Inculated the sensitive variety for 48 hours,soybean plants withered and died,and the lower part of soybean stem and root of the phenomenon of softening and decay.Based on the above resules,small spores is not suitable for tieback symptom,these findings suggested that large spores of Fusarium oxysporum are suitabe for the experiment tieback Symptom.